I know there are computer interfaces for GM and Ford vehicles to mess with the ECU or CCU of the car when there are smaller or larger tires to maintain the correct speedometer readout and maintain accurate odometer miles.
Is there such a device for Toyotas with our larger tires?

Thanks.

 

I used this one in my 01 4Runner
http://www.dakotadigital.com/index.c...rod/prd126.htm

and there's this one as well

http://www.superlift.com/accessories/truspeed.asp

 

Regearing does the same thing and puts you back in the engine's powerband. But obviously thats expensive so goodluck with whichever product you use.

 

yeah, it does put you close to where stock is, but you'll never be able to get the perfect combination of gearing/tires to get it exact (for mph purposes), unless by chance

that is where the computer comes in, it can take inputs for your gearing, and tire size (which should be measured, not from what the sidewall says) and then with your rpm's, calculate the exact signal that your speedometer needs to get to be correct (with a very small margin of error)

and if you want to be really exact, get a gps that has display for speed in real time
(of course it would also have to compensate for the curvature of the earth, and to be 100% exact it would need a flux capacitor )

 

When most people regear, they use a ratio that's significantly lower than stock and more than enough to make up for the difference in tire size, so the speedometer will still be off.

 

When I put bigger tires on my 02 Taco I called the dealer and asked if they recalibrated speedometers. They told me they send them out and referred me to the company that does it. I walked in paid $50 and 20 minutes later my speedo was calibrated.

 

Yeah,
I used the Marks Adaptors Speedo Ratio Box. Very nice and compact unit, easily hidden and very easy to wire in. Has 2 settings, 1 for everyday tyres and 1 for play.

Heres a link to the site, its from Australia, but I dont see why you couldnt import them. Pretty affordable at around $165 Australian.

http://www.marks4wd.com/products/tyr...orrection.html

 

Gears have no effect on the speedo on 03+ 4runners.

 

why, and what about 05+ tacos?

 

That's what I've been wondering. I went to 33s on my '06 Tacoma, and according to 2 different radar displays, the speedometer appears to be within 1 mile per hour just like it was with the stock tires.

Makes me wonder if the speedometer uses a GPS.

 

That's what I've been wondering. I went to 33s on my '06 Tacoma, and according to 2 different radar displays, the speedometer appears to be within 1 MPH just like it was with the stock tires.

Makes me wonder if the speedometer uses a GPS.

 

interesting... i really want to know how it does it!

 

mine's way off according to GPS. I've got 33's on my 07 Tacoma... i'm 14 km/h off the speedo. That's 8.6 Miles for you lower 49th'ers

 

Speed is taken from the wheel speed sensors (same sensors used for the abs/atrac). The only thing that will effect this is the tire size. This is for 4runners and fjc's not sure about tacos.